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    Home > Coatings News > Paints and Coatings Market > Nomenclature of organic compounds

    Nomenclature of organic compounds

    • Last Update: 2020-03-05
    • Source: Internet
    • Author: User
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    Nomenclature is the language of learning organic chemistry, so it requires learners to master it Nomenclature of organic compounds includes common nomenclature (customary nomenclature) system nomenclature and other methods It is required to be able to write the correct name of common organic compounds or write the structural formula or configuration formula according to the name Nomenclature of an organic compound 1 Common name and abbreviation Some compounds are often used according to their sources We need to know the structural formula of some compounds represented by common names For example, xylol is commonly known as alcohol (ethanol), glycol (glycol), glycerin (glycerol), carbolic acid (phenol), formic acid (formic acid), salicylaldehyde (o-hydroxybenzaldehyde), cinnamaldehyde (β - phenylacrolein), crotonaldehyde (2-butenal), salicylic acid (o-hydroxybenzoic acid), chloroform (trichloromethane) grass Acid (oxalic acid), picric acid (246 trinitrophenol), glycine (α - aminoacetic acid), alanine (α - aminopropionic acid), glutamate (α - aminoglutaric acid), D-glucose, D-fructose (the open chain structure of sugar is represented by Fisher projection formula), etc there are also some compounds commonly used in its abbreviations and trade names, such as RNA (ribonucleic acid), DNA (deoxyribonucleic acid), aspirin (acetylsalicylic acid), coal phenol soap or Lysol (47% - 5%) 3% soap water solution of three cresols, formalin (40% formaldehyde water solution), paracetamol (p-hydroxyacetanilide), nicotine (nicotine), etc 2 The common nomenclature (customary nomenclature) requires to master the meaning and usage of the words "n-isoxin", "Bozhong Shuji", etc; New: generally refers to alkanes with structure at one end of the carbon chain Primary: the carbon atom connected with only one carbon is called primary carbon atom Secondary: the carbon atom connected with two carbon is called secondary carbon atom Tertiary: the carbon atom connected with three carbon is called tertiary carbon atom QUATERNARY: the carbon atom connected with four carbon is called quaternary carbon atom For example, C1 and C5 are both primary carbon atoms, C3 is secondary carbon atom, C4 is tertiary carbon atom, C2 is quaternary carbon atom It is necessary to master the structure of common hydrocarbon groups, such as allyl allyl n-propyl isopropyl isobutyl tert butyl benzyl, etc for example: 3 Systematic nomenclature Systematic nomenclature is the key to nomenclature of organic compounds It is necessary to master the nomenclature principles of all kinds of compounds Among them, the nomenclature of hydrocarbons is the nomenclature of basic geometric isomers, optical isomers and multi-functional compounds, which is a difficult point It is necessary to keep in mind the "rules of suborder" followed in nomenclature Two example analysis 1 Nomenclature of alkanes The naming of alkanes is the basis of naming all open chain hydrocarbons and their derivatives The steps and principles of naming example 1 are as follows: (1) when selecting the longest carbon chain as the main chain and having several identical carbon chains, the carbon chain with more substituents should be selected as the main chain (2) numbering When numbering the main chain, start from the end closest to the substituent If there are several possible situations, each substituent should have the smallest number or the sum of the times of substituent positions (3) write the name with Arabic numerals to indicate the position of substituent, write the position and name of substituent first, then the name of alkane; When there are multiple substituents, the number of the same substituents can be represented by Chinese characters; Arabic numerals and Chinese characters are separated by a half character line According to this principle, the compounds above are named 2347 tetramethyloctane 2 The nomenclature of geometric isomers of olefins includes CIS trans and Ze Simple compounds can be represented by cis and trans or Ze When CIS and trans are used, the same atom or group on the same side of double bond carbon atom is cis and vice versa Example 2 If the four groups on the double bond carbon atom are not the same, they can not be represented by cis and trans They can only be represented by Ze According to the "" order rule "" compare the priority of two groups The two better groups on the same side of the double bond carbon atom are Z-type and vice versa is E-type It must be noted that there is no inevitable internal relationship between the two different representations Some compounds can be represented by cis and trans, and can also be represented by Ze Ze indicates that the CIS is not necessarily the z-trans, but not necessarily the E-type For example, there are CIS and trans isomers in the alicyclic compounds, and the two substituents on the same side of the ring plane are CIS and vice versa 3 the parent of the compound is cyclobutane, and there are two methyl groups on both sides of the ring plane, so it is the trans isomer The name is trans-13-dimethylcyclobutane 3 The name of the optical isomer There are two ways to express the configuration of optical isomers: DL and RSD There are some limitations in l-labeling method Some compounds are difficult to determine the corresponding relationship between them and the structure of glyceraldehyde Therefore, RS labeling method is more widely used It is based on the spatial arrangement of four different atoms or groups connected by chiral carbon atoms Optical isomers are generally expressed by projection to master the projection principle of Fischer projection and the judgment method of configuration For example 4, to determine the configuration according to the projection formula, first make sure that the groups connected by the horizontal line are backward to the groups connected by the vertical line in the projection formula; then arrange the priority of the four groups connected by the chiral carbon atom according to the "" order rule "" in the above formula: - NH2 > - COOH > - CH2-CH3 > - H; The smallest group hydrogen atom is regarded as the top of tetrahedron with carbon atom as the center, and the other three groups are the corner top of the triangle at the bottom of tetrahedron From the bottom of tetrahedron to the top, the clockwise of the three groups is R and the counterclockwise is s in the above formula, from - NH2 - > - COOH - > - CH2-CH3 is clockwise, so the compound represented by the projection formula is named r-2-aminobutyric acid 4 The nomenclature of bifunctional groups and multifunctional compounds the key to nomenclature of bifunctional groups and multifunctional compounds is to determine the parent group There are several common situations: ① when halogen and nitro coexist with other functional groups, halogen and nitro are used as substituents and other functional groups as the parent group; ② When the double bond and the hydroxycarbonyl carboxyl group coexist, the alkene is not the parent, but the aldehyde ketone carboxyl group is the parent ③ when the hydroxyl group and the carbonyl group coexist, the aldehyde ketone is the parent ④ when the carbonyl group and the carboxyl group coexist, the carboxyl group is the parent When the double key and the three key coexist, the longest carbon chain containing both the double key and the three key should be selected as the main chain number When the double key or the three key are numbered as low as possible, if the number of bits of the double key and the three key are the same, the double key should be numbered as low as possible Example 5 Steps and principles: (1) determine the parent group: for nitro and halogenated hydrocarbons, the parent group is hydrocarbon, and nitro and halogenated hydrocarbons are substituents Therefore, the parent group of the above compounds should be toluene (2) number: the sum of substituents should be minimized from the beginning of methyl (3) Name: the order of different substituents should be followed by the group with better order Therefore, the compound is named as: 2-nitro-3-chlorotoluene Example 6 steps and principles: (1) confirm that there are two functional groups in the parent compound according to the "" order rule "" carboxyl is superior to carbonyl, and carboxyl should be used as the parent carbonyl as the substituent (2) the number starts from one end of carboxyl (3) the name compound is named as: 4-methyl-5-oxohexanoic acid 5 The name of heterocyclic compound As most heterocyclic parent nuclei are transliterated from foreign names, transliteration is generally adopted It should be noted that the number of substituents generally starts from heteroatoms along the ring to minimize the number of carbon atoms with substituents; The heteroatoms on both sides of the heteroatom can also be arranged as ab Example 7 Steps and principles: (1) confirm that the parent compound takes pyrrole as the parent carbonyl as the substituent (2) the number starts from the nitrogen atom (3) the compound with written name is named as: 2-nitropyrrole or a-nitropyrrole
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